radio interference from wind farms

This is slightly off topic for wireless LANs but may be of interest
for other types of wireless.

UK has lots of fixed link microwave and radio / TV transmitters, so
the regulator had some field trials done to see what the effect of all
that spinning metal in a wind farm might have on the signals.

At the moment wind farms are built out of the path of fixed wireless
links, but it is difficult to do that for a TV or radio broadcast
transmitter.

wind farm radio interference
http://www.ofcom.org.uk/radiocomms/i...arm_report.pdf

brings a whole new meaning to multi path.....

Regards

Stephen
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Regards

(E-Mail Removed) - replace xyz with ntl

On Sat, 04 Apr 2009 08:53:16 -0400, News <(E-Mail Removed)> wrote:

>
>
>Stephen wrote:
>
>> This is slightly off topic for wireless LANs but may be of interest
>> for other types of wireless.
>>
>> UK has lots of fixed link microwave and radio / TV transmitters, so
>> the regulator had some field trials done to see what the effect of all
>> that spinning metal in a wind farm might have on the signals.
>
>
>The "study" does not even touch on tower and blade construction methods.
>
>Most wind machines have composite blades, no significant metal
>components except in the fixed tower and even many of these are now
>filament wound composite.

Ok - my fault for not knowing that.

doesnt seem to make the thing radio transparent though.
--
Regards

(E-Mail Removed) - replace xyz with ntl

On 5 Apr, 00:48, Jeff Liebermann <(E-Mail Removed)> wrote:
> On Sat, 04 Apr 2009 08:53:16 -0400, News <(E-Mail Removed)> wrote:
> >Stephen wrote:
>
> >> This is slightly off topic for wireless LANs but may be of interest
> >> for other types of wireless.
>
> >> UK has lots of fixed link microwave and radio / TV transmitters, so
> >> the regulator had some field trials done to see what the effect of all
> >> that spinning metal in a wind farm might have on the signals.
>
> >The "study" does not even touch on tower and blade construction methods.
>
> I never could download the PDF. *It hung at about 50%. *I tried it on
> several computers with identical results. *All the previous pages on
> the Ofcom site work, but not the PDF download:
> <http://www.ofcom.org.uk/radiocomms/ifi/licensing/classes/fixed/Windfa...>
> Can someone email me a copy?

Scented:-)

On Sat, 04 Apr 2009 16:48:13 -0700, Jeff Liebermann <(E-Mail Removed)> wrote:


>Yep. Officially, the blades are "pultruded glass-reinforced plastic"
>also known as fiberglass:
><http://en.wikipedia.org/wiki/Glass-reinforced_plastic>
>The blades are fairly transparent to RF, but not totally. Depending
>on the filler and additives used, the blades can act as an RF
>absorber. While not as dramatic as a rotating metal blade, a rotating
>absorber will have some slight effect on RF reception, especially in
>weak signal areas.

They also affect ATC radar.

--
Geo

"Geo" <hw9j-(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
: On Sat, 04 Apr 2009 16:48:13 -0700, Jeff Liebermann <(E-Mail Removed)>
wrote:
:
:
: >Yep. Officially, the blades are "pultruded glass-reinforced plastic"
: >also known as fiberglass:
: ><http://en.wikipedia.org/wiki/Glass-reinforced_plastic>
: >The blades are fairly transparent to RF, as an RF
: >absorber. While not as dramatic as a rotating metal blade, a rotating
: >absorber will have some slight effect on RF reception, especially in
: >weak signal areas.
:
: They also affect ATC radar.

Likely that is a bit of self servicing misinformation from the anti groups.
I would more expect a claim against Doppler wind sheer detection devices and
perhaps weather radar.

On that note: I see lots of weather radar reports from all over but not one
mention of any notice of a wind farm. Recall weather radars are designed to
detect things that go round and round.

On Sun, 5 Apr 2009 13:26:34 -0500, "NotMe" <(E-Mail Removed)> wrote:


>Likely that is a bit of self servicing misinformation from the anti groups.
>I would more expect a claim against Doppler wind sheer detection devices and
>perhaps weather radar.

Negative.
In a particular case in the North of the UK a major airport's radar system has
been moved about 20 miles from the airport to reduce the problems created by a
large windfarm.

--
Geo

On Sun, 05 Apr 2009 18:14:49 -0700, Jeff Liebermann <(E-Mail Removed)> wrote:

>On Sun, 5 Apr 2009 13:26:34 -0500, "NotMe" <(E-Mail Removed)> wrote:
>
>>Likely that is a bit of self servicing misinformation from the anti groups.
>
>Nope. The BWEA (British Wind Energy Assoc) is a industry group
>representing the interests of wind power producers in the UK.

>Sorta. ATC radar is easy as all aircraft are require to have
>transponders and encoding altimeters that squawk whatever the tower
>assigns. When outside the TCA (tower controlled airspace), they
>squawk 1200. Unless someone install a transponder on a wind farm, it
>should be easy to distinguish a wind turbine from an aircraft.

Sorta - but in the UK not all light aircraft (yet) have to have a transponder.

>While there may be some flashes and shadows caused by wind farms,
>unless its on the approaches, the tower isn't going to be overly
>concerned as they're always in the same location. ATC radar has an
>"ignore this" feature, where a simple stab of the light pen, will
>either blank or reduce the sensitivity in the selected area.

Unfortunately the specific wind farm which resulted in the radar facility having
to move is on high ground and occupies (estimated) 120 degrees of the available
360.

--
Geo